With the primary election just days away, Leah Vukmir came out swinging against charges that she was a latecomer in supporting President Donald Trump.

In unusually blunt terms, Vukmir took issue with a digital ad by her rival Kevin Nicholson and criticized a third-party group that has attacked her with millions of dollars in spending during the heated Republican primary for U.S. Senate.

Vukmir's counterattack came after last week's release of a March 2016 video in which she called Trump "offensive to everyone" and held her nose while describing what Republicans thought of the idea of voting for him.

Vukmir, a state senator from Brookfield, and Nicholson, a Delafield businessman, are battling in the Aug. 14 primary, with the winner meeting Democratic U.S. Sen. Tammy Baldwin in November.

"I'll cut right to the chase," Vukmir told the Milwaukee Journal Sentinel on Monday.

"These are desperate tactics from a guy who claims to be on the outside yet he is using D.C. swamp campaign strategy plain and simple," Vukmir said of Nicholson, whose digital ad featured the 2016 video footage.

"And, honestly, I think most people are sick of this," Vukmir said.

She also said there was "hypocrisy" in Nicholson receiving support from the national Club for Growth, calling it "astounding" that the group that opposed Trump in 2016 was now coming after her.

"We know the Club for Growth," she said. "It spent millions against Donald Trump in that election cycle."

She added that in 2012, Club for Growth spent heavily against businessman Eric Hovde and former Gov. Tommy Thompson in a GOP Senate primary that Thompson won.

Vukmir pointed out that Nicholson's campaign consultant, Axiom Strategies, was founded by Jeff Roe, a senior strategist of Ted Cruz's presidential campaign. Cruz, a U.S. senator from Texas, and Trump battled for the GOP nomination.

"This is just desperation on the part of a campaign that knows I'm winning," she said.

In a statement, Nicholson responded: "Republican voters are concerned about sending a career politician to Washington who won’t support the president’s agenda when push comes to shove — that’s a fair concern given what they’ve seen from too many in Congress over the past couple years."

He added: "My primary opponent went on national TV saying she’s 'always been with' (Trump), and that’s clearly not accurate given her previous statement that President Trump is 'offensive to everyone.' That’s a significant disparity that Wisconsin Republicans should take seriously."

In an interview last week with WTMJ-AM (620), Nicholson said that he had a "tough conversation" with Cruz, telling him he voted for Trump in the Wisconsin primary. Cruz has supported Nicholson's primary bid against Vukmir.

Vukmir said she didn't see Nicholson "do anything for Donald Trump" during the final push to the 2016 election.

"I do know, his top aide, Jeff Roe, was a big never-Trumper," she said.

Vukmir said Republicans in the state "know how I stood with the president."

During the 2016 primaries, Vukmir first supported Gov. Scott Walker and after he dropped out backed U.S. Sen. Marco Rubio of Florida. In Wisconsin's primary, she voted for Cruz.

"The primary season was two years ago and let's face it, there were a lot of people who were supporting many people during that primary," she said.

During the general election, Vukmir was part of a women for Trump group and appeared on a radio ad supporting his candidacy against Democrat Hillary Clinton.

"What clearly matters is I supported Donald Trump during one of the darkest times of the campaign," she said. "When everyone was running in the opposite direction, away from him, after the 'Hollywood Access' tape, I made a very conscious decision to join with other strong women leaders from southeastern Wisconsin to record the women for Trump radio ad in the final weeks. And I know that ad made a difference."

Vukmir said she and others who were on the ad "stuck our necks out, at a time when most people would have thought we were crazy to do it, but I feel as strongly today as I did then it was the right thing to do. And it did make a difference."